JPS6099146A - Powdery ethylene-acrylic acid copolymer composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having improved pulverizability without lowering the original characteristics of the base resin, without using a refrigerant, by mixing and kneading an ethylene-acrylic acid copolymer with less than equal amount of polyethylene, and pulverizing the mixture mechanically at normal temperature. CONSTITUTION:The objective composition can be produced by kneading (a) an ethylene-acrylic acid copolymer having an acrylic acid content of 1-20wt% with (B) a straight-chain low-density polyethylene or a high-pressure low-density polyethylene having a melt index of 2-70 at a ratio (A:B) of (90-55):(10-45), pelletizing the mixture after cooling with water, and pulverizing the pellets at normal temperature with an impact or grinding pulverizer to the powder having particle diameter of 1,000-50mu (i.e. 20-250 mesh, and for fluidized bed coating, preferably 50-80 mesh). The composition may be incorporated further with conventional stabilizer, lubricant, ultraviolet absorber, and a colorant such as as pigment, dye, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ethylene-acrylic acid copolymer compositions with improved grindability. More specifically, the present invention relates to a powdered composition.

Ethylene-acrylic acid copolymer (hereinafter abbreviated as FAA) has traditionally been used as a food packaging material with various excellent physical and chemical properties such as adhesion, heat resistance, tensile strength, weather resistance, and phlegm resistance. It is widely used for laminate films and for powder coating by crushing it.

However, in order to turn FAA into a powder for coatings (fluidized dipping, electrostatic coating, baking coating, etc.), we had to rely on low-temperature pulverization. If we pulverized it using a refrigerant, we could obtain the desired powder. However, since it requires a cold source (mainly liquid nitrogen), it is economically disadvantageous; if it can be easily pulverized, an economically advantageous powder can be obtained.
Therefore, the industry has been hoping for the emergence of FAA that can be pulverized at room temperature, since its uses can be further expanded. ``In view of this situation, the inventors have conducted extensive studies, and as a result of the EA
If you add a small amount of AG polyethylene, the original EA
A's JMt Hh 4. l! It was discovered that mechanical pulverization, which can be heated at room temperature without impairing the I-injection properties, is uT HQ, and therefore an inexpensive powder can be obtained, leading to the present invention.

That is, the object of the present invention is to provide an FAA resin composition that is easily pulverized at room temperature. This is an ethylene-acrylic acid copolymer composition.

EAA used in the present invention is prepared by copolymerizing ethylene free radicals and acrylic acid through high-pressure reaction.

Generally, EAA with an acrylic acid content of 1 to 20@11% is suitable for the purpose of the present invention.

The polyethylene used in the present invention may be high-pressure low-density polyethylene or rectangular low-density polyethylene having a melt index of about 2 to 70 at a suitable temperature depending on the purpose.

The blending ratio of FAA and polyethylene is 90-55:10-4
A range of 5 is suitable for the present invention. EAA
If there is too little, the characteristics will not be exhibited, and if there is too much, it will be difficult to grind at room temperature.

The kneading method for EAA and polyethylene is hot roll,
A melt mix method using a Negoo mixer, a Banbury mixer, or an extruder is used, and it is convenient and preferable to knead and water-cool pellets using a stand-off extruder.

In this case, a stabilizer is commonly used in powder coating resins.

In addition to additives such as lubricants and ultraviolet absorbers, coloring agents such as pigments and dyes can be mixed at the same time, and the formulation is determined depending on the intended flea.

After kneading, the material is pulverized to a predetermined size according to the purpose.The feature of the present invention is that it can be mechanically pulverized at room temperature, and conventional commercially available impact type or grinding type can be used as appropriate. be able to.

The size of the powder is usually 1000~50μ (20~25μ).
For fluidized dipping, a medium particle size of about 50 to 80 mesh is preferred.

Powder coating method or fluid dipping method 1 Electrostatic coating method, sprinkling method etc. There are no particular limitations and the decision should be made in consideration of the product type, size, economics, etc. The law is often used.

The present invention will be explained in detail below using Example t, but it goes without saying that the present invention is not limited to the Examples.

Example 1 gAA (acrylic acid content: 6.6%; M I 9.0;
quotient, arw-x -h C1yX -1an:8 + l + iv, s = ) 10n ~ in Heavy weight part and linear low density polyethylene (product name NZ-25100; Mitsui Petrochemical Systems, MIIO) 0 ~ 50 weight The diameter of the part is L
/D: The extruder No. 25 was kept at 140° C. to knead and extrude the resulting water-cooled pellets, which were then mechanically pulverized at room temperature.

The physical properties of the powder are shown in Table 1 in comparison with conventional frozen crushed products. The results of this pulverization are also shown in Table 2.

The physical properties of the composition according to the present invention 42 are shown in Table 8 in comparison with those of FAA.

Table 1 Table 2 Table 3 Implementation #! A2 E A A (7ri') )' fusion 8%, MI=9.
Q: J-argument F A A -4590t)y Chem
(manufactured by Lea1) xoo ~ 50 parts by weight and high pressure low density polyethylene (trade name: Kumikase: /G-701M I
= 7 (manufactured by Sumitomo Chemical) o ~50 parts were extruded and made into water-cooled pellets, which were mechanically pulverized at room temperature. The pulverization results are shown in Tables 4 and 455).

iJ4 Table Example 3 FAA (acrylic throat absorbent 12%, MI17.Product name:
100 to 50 parts by weight of Yukan-X-192 Mitsubishi Yuka*) and low-density polyethylene (product name: 0220200M)
I20. (manufactured by Mitsui Petrochemical) θ~50i parts were extruded and made into water-cooled pellets, which were mechanically pulverized at room temperature. The pulverization results are shown in Tables 6 and 7.

Table 6 Table 7 As shown above, the uninvented composition has good pulverizability, good powder physical properties and good fluidity due to fluid dipping, and the coated one has strong properties (1, maintaining adhesion and coating physical properties). Also EA
It was as good as the product A alone and could be used for powder processing using light.

Applicant Steel Chemical Industry Co., Ltd. Representative Hiroshi Sasaki

Claims (8)

[Claims] (1) A powdery ethylene-acrylic acid copolymer composition obtained by kneading, mixing, and pulverizing ethylene-acrylic acid copolymer and polyethylene in equal or less amounts. (2) The composition according to claim (1), wherein the acrylic acid content of the ethylene-acrylic acid copolymer is 1 to 20% by weight. (3) The composition according to claim (1), wherein the blending ratio of the ethylene-acrylic acid copolymer and polyethylene is 90-55:10-45. (4) Low-density polyethylene with linear polyethylene (
The composition according to claim (1), which is L-LDPK). (5) The composition according to claim (1), wherein the polyethylene is high-pressure low-density polyethylene. (6) The composition according to claim (1), which is kneaded using an extruder and then mechanically pulverized without using a refrigerant. (7) The composition according to claim (6), wherein the mechanical crushing is by impact or grinding. (8) The composition according to claim 11, (61 or (7)), wherein the particle size of the powder is 50-1000μ.